Many aircraft include a landing gear assembly comprising a pivotable bogie such that when the aircraft is on the ground, the bogie is generally aligned with the ground, whereas just prior to landing, and immediately following take-off, the bogie can be trimmed at an angle to the ground. Trimming the bogie in such a way provides a number of advantages as will be understood by the person skilled in the art.
It is advantageous to be able to stow a landing gear assembly during flight, and more particularly to stow the landing gear assembly within a particular area of the aircraft. To efficiently use the available space, it is therefore particularly advantageous to be able to position the pivotable bogie between the above-mentioned trimmed configuration, and a stowable position. In general, the stowable position will be such that the bogie is at a specific angle, and often such that it is untrimmed and/or is perpendicular to the leg of the landing gear.
It is known to trim aircraft landing gear bogies using pitch trimmers as linear actuators. Often these pitch trimmer actuators are also additionally configured to position the bogie for stowage. Such an arrangement is shown in U.S. Pat. No. 6,575,405, which is incorporated herein by reference it its entirety. However, such arrangements are often unduly heavy, bulky and/or complex. For example, the pitch trimming arrangements of U.S. Pat. No. 6,575,405 would appear to be subjected to the significant loads generated during both take-off and landing of the aircraft. The pitch trimming arrangements must therefore be especially strong, and may be unfavourably heavy. Furthermore, in the case of a pitch trimmer in the form of a hydraulic ram or the like, considerable loads are transmitted via hydraulic fluid, which is particularly undesirable.